Titan: War of Worlds
by gabrielchiong11
Summary: A Gate has opened, creatures which people from the other side called it "Titans" stepped forth out of the portal and began wreaking havoc. As though destiny had called them, two worlds and many civilizations will be involved in this war. A war that was soon to be called a "War of Worlds". Inspired by UNPeackeeper's story "War of the Worlds"


**gabrielchiong11 here and I'm new to the AoT Fanfic Community.**

 **This fic is based around my Alternate Timeline in a crossover section of Hearts of Iron series and GATE. (If you know it, I highly suggest reading the Timeline before starting the actual chapter. Because you might misunderstandings on how I based off and how I make this story).**

 **Anyways, please forgive me if I have bad grammar and this is an AU fic. Don't you ever forget about it.**

 **Inspired by UNPeacekeeper's story "War of Worlds"**

 **Now without further adieu let's begin.**

 **Disclaimer: I don't own Attack on Titan nor the elements used in the story. Everything belongs to their respective owners.**

 **PS: Please note that this chapter is subject to change whenever I feel like it.**

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 **Berlin, March 1950**

 **Nighttime**

It was nighttime, it was clearly so for Obersleutnant Eren Jaeger of the former 511th Schwere Panzerabteilung of the Wehrmacht, now the 4th Panzer Battalion, stationed in Berlin.

There were rumors about this man. He was called the ever "suicidal bastard" by one of his certain classmates during his days as a cadet more than a two decades ago. He was a part of the former 511th Schwere Panzerabteilung as a Hauptmann of the 2nd Panzer Company.

During the closing days of the Second World War, the Battalion he had been a part of was recommissioned to the western front to combat the Allied Powers invading there. He could still remember the name of the battle the Americans called a few years back.

 _The Battle of the Bulge. Quite an interesting name those Americans like to call it._

Eren made a small smile at the memory as he softly clutched his missing left arm, making him remember how he had lost his arm.

It was during the heat of battle, it was when Allied firepower was too much for his comrades at the Siegfried Line back in 1943. He could still remember the pain he felt when an HE Shell exploded when he failed to completely escape the Tiger Tank and lost his left arm and leg.

He would've died due to the loss of blood, he could remember that experience all to well and he knew he should've died if it weren't for a Japanese soldier to give him actual mercy and even have the guts to let the German Hauptmann treated in a nearby Allied Field Hospital. Of course, he went under a coma before the soldier had reached the Field Hospital for his wounded body to be treated.

He lost conciousness for a few days, it was until then he woke up with the smell of blood and medicine invading his nose. He could always remember the name of the soldier who saved him.

 _Leutnant Itami Youji, I've never expected a soldier like you to be my savior in my time of need._

Eren thought, as memories of his many conversations with him when he was recovering in one of the beds of the Field Hospital. He even chuckled when the man tried to speak German but it was only mediocre at best, but he could master it when given the time.

He was a wounded POW, but he wasn't treated as an actual POW. He never experienced as an actual POW when the War ended just a week before his recovery.

After the War, he was then sent to an intact Hospital in Germany for rehabilitation and was given a prosthetic leg as a replacement of his lost him. But he refused the offer of having a prosthetic left arm, stating as a reminder how cruel and deadly war can be, and it was also a reminder that not every Japanese soldier is as he seemed as they are.

When the Bundeswehr was formed, he was then promoted to a Major then to his now current rank Oberstleutnant of the designated 4th Panzer Battalion. A combined German Armored Force and one of the few Tank Battalions stationed in Berlin for a year now.

Of course, when as a disabled man with two missing limbs still continuing his services to the military shocked most of the new, raw recruits of the Deutsches Heer branch of the Bundeswehr. To his surprise, or the lack thereof, is that they're missing experienced field-graded officers for the military. One of the many people were call back to the military was Eren Jaeger and some men from his former Battalion.

After some time had passed, he was ordered to go to a local Bar in Mitte, a district located in Berlin. He was told a messenger, personally ordered by Chancellor Rommel, will be meeting him and few other Commanders from other Battalions stationed in Berlin.

Eren stood in front of the establishment. The bar seemed familiar, as well as the name and symbol used for the logo.

It has two wings intertwined with each other. The right wing has a color of white and the other blue. The name seemed rather peculiar.

"Bar Flügel der Freiheit (Wings of Freedom) an interesting Bar name. How come I never knew an establishment such as this, I wonder?"

Eren quietly uttered those words out of his mouth as the left, armless sleeve of his black overcoat blown softly by the wind. He silently shook those thoughts off and went inside the building.

The place was spacious, it was expected as a bar that was newly established and with the thought it would attract many customers in this bar.

Eren took a vacant seat at the front bar and ordered a glass of water for him to drink.

While he was waiting for his order, a familiar voice called out from behind.

"Hey Jaeger! it's been awhile! How've you been?!" a familiar voice soon called out to Eren.

Knowing the owner of the voice he replied, "No need to shout out loud, Horse-face."

The man who was nicknamed "Horse-face" was known as Obersleutnant Jean Kirschtein, the Commander of the 2nd Panzer Battalion stationed in Berlin. He was well known for his leadership during the war at the Eastern Front as part of the 501st SS Panzerabteilung. Even though he was a selfish asshole who only thinks for himself back when they were recruits, he then have a change of heart after he fought at the Eastern Front. Most notably, the Battle of Stalingrad.

Jean ignored the nickname, feeling a bit too old for him to reply insults back to him. He answered.

"You haven't changed at all Jaeger! Just like back in our days as trainees, you Suicidal Bastard."

Eren chuckled at the nickname he was given back they were recruits and responded.

"You haven't changed as well Kirschtein. And here I thought the Eastern Front made you kick the bucket, guess I was wrong."

"You and your stupid little jokes as always. Jokes aside, still can't believe we're still alive after the war and all. Here I thought I would be resting in one of the graveyards of the Fatherland."

"Yeah, me too. Can't believe it as well, Jean." Eren replied, taking out a folded photo from his pocket and stared at the picture.

Noticing the photo, Jean quietly asked almost like a whisper.

"You still missed them... don't you... Jaeger?"

"...Yeah." he answered.

When you take a look of the photo, you see three kids. Though it was colored black and white, he could remember the color of their hair and eyes.

The left of the photo was a young girl — part Japanese and part German — her name was Mikasa Ackermann. At the middle was him, Eren Jaeger. And on the right was Armin Arlert, a short blonde-haired boy with bright-blue eyes.

This was a photo taken back when they were kids, Eren could still remember the happy moments he felt with his childhood friends just by looking at their faces on the photo alone.

But now, they are dead. Just remembering that part made Eren's heart churned at the memory of it.

Mikasa Ackermann, died on a bombing raid made by the British and American forces in 1942 in Berlin. She was his lover, he had promised to himself that he'll marry her after the war, now that promise was broken when she was killed during the raid.

Hauptmann Armin Arlert, KIA. Cause of death, killed by a bullet wound to the head. It was during an Allied amphibious landing of Europe when it happened. Fought heroically and valiantly for the Fatherland against the Allies in mid 1943. A part of him regretted that he wasn't there for his friend at Normandy, but still, the past is in the past he couldn't prevent after all it had happened.

Looking at his fellow officer dead silent, Jean spoke.

"Sorry for bringing up about their deaths, Jaeger. I didn't mean to, I swear! If only we have the right information, we would've known where the Allies had planned their invasion we could've won! But now they're dead, especially my friends, our friends, Marco, Reiner, Bertholdt, and hell! Even Connie was killed! So I guess we're pretty even, huh, Jaeger?"

Eren let out a small, emotionless chuckle, "Don't say it like that Jean. It was war, it was completely necessary to put down your life for the nation. Their sacrifice weren't in vain, the new generation would take their place and thereon, they will do the same thing as their predecessors have done years ago."

Jean let out a familiar snort, "Now that's the Suicidal Bastard I know about years ago! But hey, question. Where's the messenger the higher-ups ordered us to meet? Can't seem to find him anywhere?" Jean asked as he looked around.

 _Indeed,_ Eren thought as he looked around, _Where's the messenger we were ordered to meet? Could the messenger be a woman?_ Erenshook his head, _Probably not, after all, every establishments that sells alcoholic beverages barred every women from coming here._

Before Eren could continue to ponder his thoughts. The man — the one who observing Eren for awhile — suddenly spoke.

"Excuse me?" the man began, catching Eren and Jean's attention. "Are you two, Obersleutnant Jaeger and Kirschtein? Commanders of the 4th and 2nd Panzer Battalion respectively." he asked, while earning Eren and Jean's questioning looks.

"Yeah, that's us... Why?" Jean answered, the man have blonde haired, with cold-blue eyes. He seemed something out of a description based by the Führer about the superior human race — the Aryan Race — and it was something to see someone like that of the description to appear so suddenly, especially when he noticed the man has a missing right arm.

"...Just asking." he said, "A certain person had called me earlier this afternoon. The person described that two men, one with brown hair and unusual suicidal attitude, and the other with a face that looks like a Horse and has Brown hair."

After the man had said those words, especially the part about having a horse face, made Jean flushed red in embarrassment and snapped.

"Who the hell do you think I have a horse for a face?! You shitty bastard!" Jean exclaimed, feeling insulted as he grabbed the man by the collar of his clothes. The only person who had gall to call him that was besides him.

"Calm down Kirschtein, I think the man was just testing us." Eren calmly said, as Jean finally cooled down a bit.

"Whatever you say Jaeger." he muttered as he calmed down.

Seeing him calmed down a bit, the man spoke.

"Guess I was right. The both of you must be Jaeger and Kirschtein. My name is Erwin Smith, the owner of this establishment, nice to meet you." the now named Erwin Smith introduced himself and lifted his only hand for a handshake.

"Likewise," Jean shook Smith's left hand.

"Nice to meet you, sir." Eren shook Smith's hand — with some difficulty — after he finished with Jean's.

After some short introductions, Erwin Smith suddenly spoke quietly.

"Let's talk somewhere else," he said before he called out, "Eld, you'll take what happens here. I'll be right back as soon as I finished talking with these gentlemen here."

The tanned-skin man, who Eren assumed to be Eld, nodded, "Of course, hope you finished talking those men. We'll probably have another big night ahead of us, sir."

Smith nodded and smiled, before leading the two Commanding Officers outside the Bar. It was snowing very lightly, considering the weather had calmed down over the recent weeks, especially when spring is about to come.

It was but a moment, when Erwin Smith suddenly stopped when they walked to an alley close to the establishment.

"I'm glad the both of you came." he spoke out loud, "Chancellor Rommel was getting worried about the state of affairs that has happened in the world after the war."

Though it was an unrelated topic of what the message was all about. Jean, being one of the smart men of the Panzer Division stationed in Berlin, immediately questioned the man.

"What do you call us here for? Don't tell me the Romans are at it again?" he said rather sarcastically.

It was merely a nickname to those invaders from the another world — AKA the Saderans — back at the Ginza Incident back in September 2nd 1945. It had happened when they launched an unexpected attack on the Capital City of the Japanese Empire.

But as of now, the Gate has been closed for nearly three years now when the Demigoddess, Rory Mercury, had warned the NWEF and the other army — also from another world — about the two Gates being closed.

There were tearful farewells to those who established friendship and kinship to that world. There were also some locals of that world had come to this world with the decision that they will be first Foreign people from another world to live in this modern world — or by those from the Gate of Alnus Hill, the Cold War Period — as such, they've been serving the military they chose. One of those were the Bundeswehr.

"Something similar to that."

The way he spoke that he recognized something was wrong. Jean and Eren recognized it the moment uttered those words out of his mouth. Eren took the initiative.

"Don't tell me." Eren spoke as if he knew what was going on, "A Gate has appeared once more, hasn't it?"

Smith nodded, confirming Eren's suspicions. Jean was shocked, it was only meant to be a joke.

 _Me and my goddamned mouth._ He knew better that his mouth has the tendency to jinx things up when situation was not expecting it to happen.

Smith replied, "Indeed, what you said is true. A Gate has appeared, at the Pyongyang region in the Northern part of Japanese Korea and just near to the Yalu river."

"Why are telling us this? Sure a Gate has opened but it isn't that shocking when... It's not Falmart on the other side, isn't it?"

Smith nodded, "Yes, reports stated from the Japanese that the other side is not Falmart at all." he paused before he continued.

"However, that report was just made this week and the Gate has appeared only just a month ago."

 _Strange,_ Eren thought, _If we're dealing another fantasy-like army, wasn't it supposed to be easily secured in just a day instead of an entire month?_

The more Eren thought about it, there was something off. Indeed, just thinking about it made Eren saw some unexpected visions.

 _ **Mom! Mom!**_ A young boy called out in a black background, sounding desperate.

Eren recognized that voice, it was his when he was young.

 _ **Eren.**_ A woman weakly called his name.

He also recognized that voice as well, it was his mother's.

 _ **Mikasa! Grab that end! We gotta move this pillar!**_ The Battalion Commander could hear giant footsteps boomed around the black background.

 _ **Hurry Mikasa!**_

 _ **I know!**_

After hearing the girl's name as well as her voice made the Obersleutnant wanted to see what this strange vision was all about.

 _ **The Titans have gotten inside, haven't they?**_ Eren's mother began fearfully, while he wondered what was something the word "Titan" was all about.

 _ **Eren! Take Mikasa and run away! Hurry!**_

He could hear his mother's voice filled with fear. Just before the vision could continue it suddenly ended. And Eren stood the same spot in alley, seemingly just as the same time the vision appeared.

 _What was that?_ he thought, _That was no ordinary dream nor vision either._

"Hey Jaeger," Jean spoke out to Eren in a shocked voice, "Did you experience what I, we, have experienced just now? About Titans and stuff."

Eren widened his eyes in shock, "Yeah..." he could feel his voice trailing off.

"—I see." Smith suddenly spoke, "So it wasn't only me that was affected as well."

"What do you know about it?!" Jean exclaimed. For the first time after the Second World War, Eren had agreed with his fellow officer after their previous disagreements made in the past.

"It's only a theory, but it would seem that the appearance of the Gate revealed events that haven't happened here. But rather on the other side."

 _That theory is more likely an answer rather than an assumption,_ the two thought simultaneously.

"Tell me. Did the Imperial Japanese Army in Korea faced an enemy which our vision had called Titans?" he asked, and the man nodded.

"Great, now it made perfect sense." Jean said in a sarcastic tone, "On top of it all, they've facing this enemy for more than a month without even informing the ENTIRE FUCKING WORLD WHAT THE FUCKING HELL IS HAPPENING THERE!"

The Jean said those words it was akin to a cursing rather than an actual comment of some kind.

"Calm down Jean. I'm sure they have their reasons for not telling us about the threat they faced in Korea. Am I right Smith?"

"Indeed that is true Jaeger." the man said, "That is why Chancellor Rommel had wanted to secretly call in several men ranging from a Battalion officer to an actual General if they experience the same thing you gentlemen have experienced."

"As for why they haven't informed the alliance and the world about it. It was because of the possibility that the entire world would be shocked that another Gate has opened. You want to experience how stressful it is to keep the other Great Powers in check if they wanted to downright invade Japan, and possibly the entire alliance, just to get the Gate for their own purposes? As such, they have decided to tell trusted allies rather than spreading information with the huge risk of the said information being leaked."

The two officers looked at the ground, feeling a bit ashamed if they randomly spread what they learn and possibly being caught by treason.

"A few months from now." Erwin Smith began, "Chancellor Rommel will be personally choosing a secret expeditionary force along with the Japanese to the other side of the Gate. A minimum of three Divisions have been selected for the upcoming expedition at the Gate. The Deutsches Heer expedition force will be under General Levi Ackermann's command. As such, the division that you two were a part of have been chosen to be in the expedition force. Therefore, pack your things and make some farewells to love ones in advance if you two were to be accidently killed in action."

Though that last part was merely a joke. But for those two who had seen, breathed, and fought an actual war. They understand it as a warning.

"The both of us here are dedicated to this nation, as well as the entire GACOPS Alliance, sir!" the two declared simultaneously and saluted as well.

Smith smiled in satisfaction, "Good. At least you're not dying early in that world. But you men leave, would you mind having a drink at my establishment for the night? After all, you two were ordered to meet me and have expected that you two will return to your posts tomorrow. Until then, let's have a drink, shall we?"

The two Obersleutnants looked at the man, skeptical but rather accept the offer since they were to return by tomorrow morning.

 **To Be Continued.**

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 **And cut!**

 **Well, this is a surprising start of my new story. Anyways, after this chapter will be a timeskip of a few Months to a year depending on what should I do about.**

 **If you starts sending me reviews and PMs about "Why Mikasa and Armin are dead?! You ungrateful bastard!" or "Dammit! You killed off my ship!" and other similar statements.**

 **Like I said above, this chapter is likely subject to change. And I'm testing the waters with the die hard AoT Anime and Manga fans that are probably at the border of dedication like the Imperial Japs and Nazi Germans in WW2.**

 **Anyways, this was story was inspired by UNPeacekeeper's "War of Worlds"**

 **Be sure to fav or follow or do a both if you like and be interested in my story of Attack on Titan: Thus They Fought There. And be sure to review and PM me if you have ideas or suggestions for my story.**

 **PS: Please PM me if you a better story title than mine. *whispers* I don't trust my brain that much.**

 **gabrielchiong11 out!**


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